The case of the lioness with the mystery mane has been solved, thanks to veterinarians at the UT College of Veterinary Medicine.

Last year, Bridget, an 18-year-old female lion at the Oklahoma City Zoo, started growing a mane!

Male lions usually begin growing a mane when they are about 1-year-old, which is when they begin producing more testosterone. It's very rare for female lions to sport a mane.

So why?

Vets managed to get a blood sample from Bridget, and sent it off to the UT vet school for analysis, and the results are in!

There's a long, scientific explanation, which you can read here, but basically what they found were elevated levels of cortisol and androstenedione.

Cortisol is a hormone produced in the adrenal glands, which is a small endocrine organ located near the kidneys that regulates most body systems including immune response and metabolism.

Androstenedione is produced in the adrenal and reproductive glands and can contribute to the development of certain androgenic (male) traits or features.

"These results most likely indicate a benign hormone-secreting tumor has developed in one of Bridget’s adrenal glands," said OKC zoo staff.

They will continue to monitor her health, which so far is excellent. They don't believe she will develop any health concerns because of it.

They're not sure if the mini-mane will continue to grow, but its not affecting her quality of life.